wayland/surface: NULL check surface resource in handle_output_bound()

Otherwise binding new wl_output's might try to send enter to the
destroyed resource. Fixes the following crash:

     #0 wl_resource_get_client at ../src/wayland-server.c:801
     #1 handle_output_bound at ../src/wayland/meta-wayland-surface.c:1287
     #3 signal_emit_unlocked_R.isra.0 at ../gobject/gsignal.c:3812
     #6 ffi_call_unix64 at ../src/x86/unix64.S:104
     #7 ffi_call_int at ../src/x86/ffi64.c:673
     #8 ffi_call at ../src/x86/ffi64.c:710
     #9 wl_closure_invoke at ../src/connection.c:1025
    #10 wl_client_connection_data at ../src/wayland-server.c:438
    #11 wl_event_loop_dispatch at ../src/event-loop.c:1027
    #12 wayland_event_source_dispatch at ../src/wayland/meta-wayland.c:125
    #15 g_main_context_iterate.isra.0 at ../glib/gmain.c:4276
    #17 meta_context_run_main_loop at ../src/core/meta-context.c:482

Related: https://bugzilla.redhat.com/show_bug.cgi?id=2196527
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2992>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index 73aeb18ba..abd5dae15 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -1283,6 +1283,9 @@ handle_output_bound (MetaWaylandOutput  *wayland_output,
                      struct wl_resource *output_resource,
                      MetaWaylandSurface *surface)
 {
+  if (!surface->resource)
+    return;
+
   if (wl_resource_get_client (output_resource) ==
       wl_resource_get_client (surface->resource))
     wl_surface_send_enter (surface->resource, output_resource);